U.S. patent application number 15/065192 was filed with the patent office on 2016-06-30 for bearing assemblies, apparatuses, and motor assemblies using the same.
The applicant listed for this patent is US Synthetic Corporation. Invention is credited to Kenneth E. Bertagnolli, Mark P. Chapman, Nicholas Edward Christensen, Damon B. Crockett, Jair J. Gonzalez, David P. Miess, Debkumar Mukhopadhyay, S. Barrett Peterson, Mohammad N. Sani, Ronald W. Ward.
Application Number | 20160186805 15/065192 |
Document ID | / |
Family ID | 48610225 |
Filed Date | 2016-06-30 |
United States Patent
Application |
20160186805 |
Kind Code |
A1 |
Peterson; S. Barrett ; et
al. |
June 30, 2016 |
BEARING ASSEMBLIES, APPARATUSES, AND MOTOR ASSEMBLIES USING THE
SAME
Abstract
Bearing assemblies, apparatuses, and motor assemblies using the
same are disclosed. In an embodiment, a bearing assembly may
include a plurality of superhard bearing elements distributed
circumferentially about an axis. Each of the superhard bearing
elements may include a bearing surface. At least one of the
plurality of superhard bearing elements may include at least one
texture feature that may be formed in a lateral surface thereof.
The bearing assembly may also include a support ring that carries
the superhard bearing elements.
Inventors: |
Peterson; S. Barrett; (Orem,
UT) ; Gonzalez; Jair J.; (Provo, UT) ;
Bertagnolli; Kenneth E.; (Riverton, UT) ;
Mukhopadhyay; Debkumar; (Sandy, UT) ; Miess; David
P.; (Highland, UT) ; Chapman; Mark P.; (Provo,
UT) ; Ward; Ronald W.; (Pleasant Grove, UT) ;
Christensen; Nicholas Edward; (Spanish Fork, UT) ;
Crockett; Damon B.; (Mapleton, UT) ; Sani; Mohammad
N.; (Bracknell, GB) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
US Synthetic Corporation |
Orem |
UT |
US |
|
|
Family ID: |
48610225 |
Appl. No.: |
15/065192 |
Filed: |
March 9, 2016 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
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13432224 |
Mar 28, 2012 |
9297411 |
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15065192 |
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|
13234252 |
Sep 16, 2011 |
8950519 |
|
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13432224 |
|
|
|
|
13116566 |
May 26, 2011 |
8863864 |
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13234252 |
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Current U.S.
Class: |
384/282 ;
29/898.062 |
Current CPC
Class: |
E21B 4/003 20130101;
F16C 33/1085 20130101; Y10T 29/49645 20150115; F16C 17/02 20130101;
F16C 2240/42 20130101; B21K 1/04 20130101; F16C 2240/48 20130101;
F16C 17/04 20130101; F16C 2352/00 20130101; F16C 33/26 20130101;
F16C 2206/04 20130101; F16C 37/002 20130101; F16C 2206/82 20130101;
F16C 33/108 20130101; E21B 17/03 20130101; F16C 33/043
20130101 |
International
Class: |
F16C 33/10 20060101
F16C033/10; F16C 33/04 20060101 F16C033/04 |
Claims
1. A method for manufacturing a bearing assembly, the method
comprising: forming a superhard bearing element that includes a
superhard table bonded to a substrate, the superhard table defining
a bearing surface and at least a portion of a lateral surface;
forming at least one texture feature in the lateral surface of the
superhard bearing element, at least a portion of the at least one
texture feature is formed in the superhard table; and securing the
superhard bearing element to a support ring.
2. The method of claim 1, wherein the at least one texture feature
is formed in the lateral surface of the at least one superhard
bearing element before the at least one superhard bearing element
is secured to the support ring.
3. The method of claim 1, wherein forming the at least one texture
feature includes at least one of laser-cutting or electro-discharge
machining the at least one texture feature in the lateral
surface.
4. The method of claim 1, wherein forming the at least one texture
feature in the bearing surface includes computer numerical control
machining the at least one texture feature in the lateral
surface.
5. The method of claim of claim 1, wherein the at least one texture
feature is effective to increase a surface area of the at least one
of the plurality of superhard bearing elements in contact with
fluid during operation.
6. The method of claim 1, wherein the superhard table includes
polycrystalline diamond.
7. The method of claim 1, wherein the texture feature includes one
or more grooves.
8. The method of claim 7, where the texture feature follows a path
substantially extending between the bearing surface of the at least
one of superhard bearing elements and a bottom surface of the at
least one of the plurality of superhard bearing elements.
9. The bearing assembly of claim 8, wherein the path includes at
least one of a generally curved path, a generally linear path, a
generally semi-cylindrical path, or a generally helical curved
path.
10. The method of claim 7, wherein the one or more groves include
two or more intersecting grooves.
11. The bearing assembly of claim 1, wherein the at least one
texture feature includes dimples, recesses, protrusions, or
grooves.
12. A method for manufacturing a bearing apparatus, the method
comprising: forming a first bearing assembly including: forming a
superhard bearing element that includes a superhard table bonded to
a substrate, the superhard table defining a bearing surface and at
least a portion of a lateral surface; forming at least one texture
feature in the lateral surface of the superhard bearing element, at
least a portion of the at least one texture feature is formed in
the superhard table; and securing the superhard bearing element to
a support ring; forming a second bearing assembly including:
securing to a plurality of second bearing elements to a second
support ring, each of the plurality of second bearing elements
including a second bearing surface; and positioning the first
bearing assembly and the second bearing assembly relative to each
other such that the bearing surfaces of the first bearing assembly
generally oppose the second bearing surfaces of the second bearing
assembly.
13. The method of claim 12, wherein the at least one texture
feature is effective to increase a surface area of the at least one
of the plurality of superhard bearing elements in contact with
fluid during operation.
14. The method of claim 12, wherein the first bearing assembly is
configured as a rotor, and the second bearing assembly is
configured as a stator.
15. The method of claim 12, wherein at least one of the second
plurality of superhard bearing elements includes at least one
texture feature.
16. The method of claim 12, wherein positioning the first bearing
assembly and the second bearing assembly relative to each other
forms a thrust-bearing apparatus or a radial bearing apparatus.
17. A method of operating a bearing apparatus, the method
comprising: rotating a first bearing assembly and a second bearing
assembly relative to each other; and directing flow of lubrication
fluid over and/or around one or more superhard bearing elements of
the first bearing assembly by influencing flow of lubrication fluid
with at least one texture feature formed in the one or more
superhard bearing elements, wherein the at least one texture
feature is effective to increase a surface area of the one or more
superhard bearing elements in contact with the lubrication
fluid.
18. The method of claim 17, wherein the at least one texture
feature is formed in a lateral surface of the one or more superhard
bearing elements.
19. The method of claim 17, wherein the one or more superhard
bearing elements include a superhard table bonded to a cemented
carbide substrate, and the at least a portion of the at least one
texture feature is formed in the superhard table.
20. The method of claim 17, wherein the texture feature includes
one or more grooves, and at least some of the one or more grooves
include edge features configured to influence the lubrication
fluid.
Description
CROSS REFERENCE TO RELATED APPLICATIONS
[0001] This application is a divisional of U.S. patent application
Ser. No. 13/432,224 filed on 28 Mar. 2012, which is a
continuation-in-part of U.S. patent application Ser. No. 13/234,252
filed on 16 Sep. 2011, now U.S. Pat. No. 8,950,519 issued on 10
Feb. 2015, which is a continuation-in-part of U.S. patent
application Ser. No. 13/116,566 filed on 26 May 2011, now U.S. Pat.
No. 8,863,864 issued on 21 Oct. 2014. Each of the foregoing
applications is incorporated herein, in its entirety, by this
reference.
BACKGROUND
[0002] Subterranean drilling systems that employ downhole drilling
motors are commonly used for drilling boreholes in the earth for
oil and gas exploration and production. Such a subterranean
drilling system typically includes a downhole drilling motor that
is operably connected to an output shaft. A pair of thrust-bearing
apparatuses also can be operably coupled to the downhole drilling
motor. A rotary drill bit configured to engage a subterranean
formation and drill a borehole can be connected to the output
shaft. As the borehole is drilled with the rotary drill bit, pipe
sections may be connected to the subterranean drilling system to
form a drill string capable of progressively drilling the borehole
to a greater size or depth within the earth.
[0003] Each thrust-bearing apparatus includes a stator that does
not rotate relative to the motor housing and a rotor that is
attached to the output shaft and rotates with the output shaft. The
stator and rotor each includes a plurality of bearing elements that
may be fabricated from polycrystalline diamond compacts ("PDCs")
that provide diamond bearing surfaces that bear against each other
during use.
[0004] In operation, high-pressure drilling fluid may be circulated
through the drill string and power section of the downhole drilling
motor, usually prior to the rotary drill bit engaging the bottom of
the borehole, to generate torque and rotate the output shaft and
the rotary drill bit attached to the output shaft. When the rotary
drill bit engages the bottom of the borehole, a thrust load is
generated, which is commonly referred to as "on-bottom thrust" that
tends to compress and is carried, at least in part, by one of the
thrust-bearing apparatuses. Fluid flow through the power section
may cause what is commonly referred to as "off-bottom thrust,"
which is carried, at least in part, by the other thrust-bearing
apparatus. The drilling fluid used to generate the torque for
rotating the rotary drill bit exits openings formed in the rotary
drill bit and returns to the surface, carrying cuttings of the
subterranean formation through an annular space between the drilled
borehole and the subterranean drilling system. Typically, a portion
of the drilling fluid is diverted by the downhole drilling motor to
help cool and lubricate the bearing elements of the thrust-bearing
apparatuses. Insufficient heat removal may cause premature damage
to the thrust-bearing apparatuses.
[0005] The on-bottom and off-bottom thrust carried by the
thrust-bearing apparatuses can also be extremely large and generate
significant amounts of energy. The operational lifetime of the
thrust-bearing apparatuses often can determine the useful life of
the subterranean drilling system. Therefore, manufacturers and
users of bearing apparatuses and subterranean drilling systems
continue to seek improved bearing assemblies and apparatuses with a
longer useful life.
SUMMARY
[0006] Various embodiments of the invention relate to bearing
assemblies, bearing apparatuses and motor assemblies that include
superhard bearing elements having texture features configured to
improve lubrication, cooling, and/or bearing capacity of the
superhard bearing elements. At least some of the superhard bearing
elements may be provided with at least one texture feature formed
in a lateral surface thereof to promote lubrication and/or cooling
and enhance bearing capacity during use.
[0007] In an embodiment, a bearing assembly may include a plurality
of superhard bearing elements distributed circumferentially about
an axis. Each of the superhard bearing elements may include a
bearing surface. At least one of the plurality of superhard bearing
elements may include at least one texture feature formed in a
lateral surface thereof. The bearing assembly may also include a
support ring that carries the superhard bearing elements. In an
embodiment, the at least one texture feature may be positioned and
configured to direct lubricating fluid over and/or around the
superhard bearing elements. In an embodiment, the at least one
texture feature may be effective to increase a surface area of the
superhard bearing elements in contact with lubricating fluid. In an
embodiment, the at least one texture feature may follow a path
extending along a generally helical curve.
[0008] In an embodiment, a bearing apparatus may include two
bearing assemblies. At least one of the two bearing assemblies may
be configured as any of the disclosed bearing assembly embodiments
that are configured to improve lubrication and/or cooling of the
superhard bearing elements during use.
[0009] In an embodiment, a method for manufacturing a bearing
assembly may include forming at least one texture feature in a
lateral surface of a superhard bearing element. The method may
further include securing the superhard bearing element to a support
ring. In an embodiment, the at least one texture feature may be
formed before securing the superhard bearing element to the support
ring. In an embodiment, the at least one texture feature may be
formed after securing the superhard bearing element to the support
ring. In an embodiment, forming the at least one texture feature
may include laser-cutting the texture feature in the lateral
surface. In an embodiment, forming the at least one texture feature
may include computer numerical control milling the at least one
texture feature in the lateral surface.
[0010] Other embodiments include downhole motors for use in
drilling systems and subterranean drilling systems that may utilize
any of the disclosed bearing apparatuses.
[0011] Features from any of the disclosed embodiments may be used
in combination with one another, without limitation. In addition,
other features and advantages of the present disclosure will become
apparent to those of ordinary skill in the art through
consideration of the following detailed description and the
accompanying drawings.
BRIEF DESCRIPTION OF THE DRAWINGS
[0012] The drawings illustrate several embodiments, wherein
identical reference numerals refer to identical or similar elements
or features in different views or embodiments shown in the
drawings.
[0013] FIG. 1A is an isometric view of a thrust-bearing assembly
according to an embodiment.
[0014] FIG. 1B is a top plan view of the thrust-bearing assembly
shown in FIG. 1A.
[0015] FIG. 1C is an isometric cutaway view taken along line 1C-1C
of the thrust-bearing assembly shown in FIG. 1B.
[0016] FIG. 1D is an isometric view of one of the superhard bearing
elements removed from the thrust-bearing assembly shown in FIG.
1A.
[0017] FIG. 1E is a side elevation view of the superhard bearing
element shown in FIG. 1D.
[0018] FIG. 1F is a top plan view of the superhard bearing element
shown in FIG. 1D.
[0019] FIG. 1G is an isometric view of a superhard bearing element
according to another embodiment.
[0020] FIG. 2A is an isometric view of a superhard bearing element
according to another embodiment.
[0021] FIG. 2B is a side elevation view of the superhard bearing
element shown in FIG. 2A.
[0022] FIG. 2C is a top plan view of the superhard bearing element
show in FIG. 2A.
[0023] FIG. 3A is an isometric view of a superhard bearing element
according to another embodiment.
[0024] FIG. 3B is a side elevation view of the superhard bearing
element shown in FIG. 3A.
[0025] FIG. 3C is a top plan view of the superhard bearing element
shown in FIG. 3A.
[0026] FIG. 4A is an isometric view of a thrust-bearing assembly
according to an embodiment.
[0027] FIG. 4B is a top plan view of the thrust-bearing assembly
shown in FIG. 4A.
[0028] FIG. 4C is a cross-sectional view of the thrust bearing
assembly shown in FIG. 4B taken along line 4C-4C.
[0029] FIG. 4D is an isometric view of one of the superhard bearing
elements removed from the thrust-bearing assembly shown in FIG.
4A.
[0030] FIG. 4E is a side elevation view of the superhard bearing
element shown in FIG. 4D.
[0031] FIG. 4F is a top plan view of the superhard bearing element
shown in FIG. 4D.
[0032] FIG. 4G is an isometric view of a superhard bearing element
according to another embodiment.
[0033] FIG. 4H is an isometric view of a superhard bearing element
according to another embodiment.
[0034] FIG. 4I is an isometric view of a superhard bearing element
according to another embodiment.
[0035] FIG. 5A is an isometric view of a thrust-bearing apparatus
that may employ any of the disclosed thrust-bearing assemblies
according to an embodiment, with the housing shown in
cross-section.
[0036] FIG. 5B is a cross-sectional view of the thrust-bearing
apparatus shown in FIG. 5A taken along line 5B-5B.
[0037] FIG. 6A is an isometric view of a radial bearing assembly
according to an embodiment.
[0038] FIG. 6B is an isometric cutaway view of the radial bearing
assembly shown in FIG. 6A.
[0039] FIG. 7 is an isometric cutaway view of a radial bearing
apparatus that may utilize any of the disclosed radial bearing
assemblies according to various embodiments.
[0040] FIG. 8 is a schematic isometric cutaway view of a
subterranean drilling system that may utilize any of the disclosed
bearing assemblies according to various embodiments.
DETAILED DESCRIPTION
[0041] Embodiments of the invention relate to bearing assemblies,
bearing apparatuses and motors, pumps, or other mechanical
assemblies that include superhard bearing elements having texture
features configured to improve lubrication and/or cooling of the
superhard bearing elements. During use, the superhard bearing
elements may not be able to effectively cool so at least some of
the superhard bearing elements may be provided with one or more
texture features (e.g., at least one groove, dimple, recess, groove
pattern, or other topography) formed therein to promote lubrication
and/or cooling during use. FIGS. 1A and 1B are isometric and top
plan views of a thrust-bearing assembly 100 according to an
embodiment.
[0042] The thrust-bearing assembly 100 may form a stator or a rotor
of a thrust-bearing apparatus used in a subterranean drilling
system. As shown in FIGS. 1A and 1B, the thrust-bearing assembly
100 may include a support ring 102 defining an opening 104 through
which a shaft (not shown) of, for example, a downhole drilling
motor may extend. The support ring 102 may be made from a variety
of different materials. For example, the support ring 102 may
comprise a metal, alloy steel, a metal alloy, carbon steel,
stainless steel, tungsten carbide, or any other suitable metal or
conductive or non-conductive material. The support ring 102 may
include a plurality of recesses 106 (shown in FIG. 1C) formed
therein.
[0043] The thrust-bearing assembly 100 further may include a
plurality of superhard bearing elements 108. In an embodiment, one
or more of the superhard bearing elements 108 may have a generally
cylindrical shaped body. While the superhard bearing elements 108
are shown having a generally cylindrical shaped body, the one or
more of the superhard bearing elements may have a generally rounded
rectangular shaped body, a generally oval shaped body, a generally
wedge shaped body, or any other suitable shaped body. The superhard
bearing elements 108 may include a superhard table 110 bonded to a
substrate 112, and a bearing surface 114 of the superhard table
110. The superhard bearing elements 108 are illustrated in FIGS. 1A
and 1B being distributed circumferentially about a thrust axis 116
along which a thrust force may be generally directed during use. As
shown, gaps 118 may be located between adjacent ones of the
superhard bearing elements 108. In an embodiment, at least one of,
some of, or all of the gaps 118 may exhibit a width of about
0.00020 inches to 0.100 inches, such as about 0.00040 inches to
0.0010 inches, or about 0.00040 inches to 0.080 inches. In other
embodiments, the gaps 118 may have widths that are relatively
larger or smaller. In other embodiments, the gaps 118 may
substantially be zero.
[0044] Each of the superhard bearing elements 108 may be partially
disposed in a corresponding one of the recesses 106 (shown in FIG.
1C which is an isometric cutaway view taken along line 1C-1C of the
thrust-bearing assembly shown in FIG. 1B) of the support ring 102
and secured partially therein via brazing, press-fitting, threadly
attaching, fastening with a fastener, combinations of the
foregoing, or another suitable technique. The superhard bearing
elements 108 may be pre-machined to tolerances and mounted in the
support ring 102 and/or mounted to the support ring 102 and the
bearing surfaces 114 thereof and planarized (e.g., by lapping
and/or grinding) so that the bearing surfaces 114 are substantially
coplanar. Optionally, one or more of the superhard bearing elements
108 may exhibit a peripherally extending edge chamfer. However, in
other embodiments, the edge chamfer may be omitted.
[0045] FIGS. 1D-1G are isometric, side elevation, and top plan
views of a superhard bearing element 108 removed from the
thrust-bearing assembly 100. As used herein, a "superhard bearing
element" is a bearing element including a bearing surface that is
made from a material exhibiting a hardness that is at least as hard
as tungsten carbide.
[0046] In any of the embodiments disclosed herein, the superhard
bearing elements 108 may each comprise one or more superhard
materials, such as polycrystalline diamond, polycrystalline cubic
boron nitride, silicon carbide, tungsten carbide, or any
combination of the foregoing superhard materials. For example, the
superhard table 110 may comprise polycrystalline diamond and the
substrate 112 may comprise cobalt-cemented tungsten carbide.
Furthermore, in any of the embodiments disclosed herein, the
polycrystalline diamond table may be leached to at least partially
remove or substantially completely remove a metal-solvent catalyst
(e.g., cobalt, iron, nickel, or alloys thereof) that was used to
initially sinter precursor diamond particles to form the
polycrystalline diamond. In another embodiment, an infiltrant used
to re-infiltrate a preformed leached polycrystalline diamond table
may be leached or otherwise removed to a selected depth from a
bearing surface. Moreover, in any of the embodiments disclosed
herein, the polycrystalline diamond may be un-leached and include a
metal-solvent catalyst (e.g., cobalt, iron, nickel, or alloys
thereof) that was used to initially sinter the precursor diamond
particles that form the polycrystalline diamond and/or an
infiltrant used to re-infiltrate a preformed leached
polycrystalline diamond table. Examples of methods for fabricating
the superhard bearing elements and superhard materials and/or
structures from which the superhard bearing elements can be made
are disclosed in U.S. Pat. Nos. 7,866,418; 7,998,573; and
8,034,136; and co-pending U.S. patent application Ser. No.
11/545,929; the disclosure of each of the foregoing patents and
applications is incorporated herein, in its entirety, by this
reference.
[0047] The diamond particles that may be used to fabricate the
superhard table 110 in a high-pressure/high-temperature process
("HPHT)" may exhibit a larger size and at least one relatively
smaller size. As used herein, the phrases "relatively larger" and
"relatively smaller" refer to particle sizes (by any suitable
method) that differ by at least a factor of two (e.g., 30 .mu.m and
15 .mu.m). According to various embodiments, the diamond particles
may include a portion exhibiting a relatively larger size (e.g., 40
.mu.m, 30 .mu.m, 20 .mu.m, 15 .mu.m, 12 .mu.m, 10 .mu.m, 8 .mu.m)
and another portion exhibiting at least one relatively smaller size
(e.g., 6 .mu.m, 5 .mu.m, 4 .mu.m, 3 .mu.m, 2 .mu.m, 1 .mu.m, 0.5
.mu.m, less than 0.5 .mu.m, 0.1 .mu.m, less than 0.1 .mu.m). In an
embodiment, the diamond particles may include a portion exhibiting
a relatively larger size between about 10 .mu.m and about 40 .mu.m
and another portion exhibiting a relatively smaller size between
about 1 .mu.m and 4 .mu.m. In some embodiments, the diamond
particles may comprise three or more different sizes (e.g., one
relatively larger size and two or more relatively smaller sizes),
without limitation. The resulting polycrystalline diamond formed
from HPHT sintering the aforementioned diamond particles may also
exhibit the same or similar diamond grain size distributions and/or
sizes as the aforementioned diamond particle distributions and
particle sizes. Additionally, in any of the embodiments disclosed
herein, the superhard bearing elements 108 may be free-standing
(e.g., substrateless) and formed from a polycrystalline diamond
body that is at least partially or fully leached to remove a
metal-solvent catalyst initially used to sinter the polycrystalline
diamond body.
[0048] Referring to FIG. 1D, at least some of the superhard bearing
elements 108 may include one or more texture features (e.g., at
least one groove, dimple, recess, pattern, other topography, or
combinations thereof) configured to influence cooling, lubrication,
and/or bearing capacity of the superhard bearing elements 108
and/or the support ring 102. For example, one or more grooves 120
may be formed in a lateral surface 108B of the superhard bearing
elements 108. In an embodiment, the grooves 120 may provide one or
more flow paths for lubricating fluid between the lateral surfaces
108B of the superhard bearing elements 108 and/or sidewalls of the
recesses 106 in the support ring 102. Such a configuration may
increase the surface area of the superhard bearing elements 108
and/or the support ring 102 in contact with the lubricating fluid
to enhance cooling the thrust-bearing assembly 100. In an
embodiment, the grooves 120 may direct lubricating fluid over
and/or around the superhard bearing elements 108 and/or the support
ring 102 to enhance cooling and/or lubrication. In an embodiment,
the grooves 120 may influence flow characteristics of the
lubricating fluid. In an embodiment, the grooves 120 may increase
bearing capacity by helping to prevent the superhard bearing
elements from overheating. For example, the grooves 120 may
increase the surface area of the superhard bearing elements 108 to
enhance heat transfer from the superhard bearing elements 108. In
yet other embodiments, the grooves 120 may increase bearing
capacity by providing engagement features for adhesives, epoxy, or
other securing elements to help secure the superhard bearing
elements 108 in the recesses 106.
[0049] The one or more grooves 120 may be formed by
electro-discharge machining ("EDM"), laser-cutting, computer
numerical control ("CNC") milling, grinding, combinations thereof,
or otherwise machining the one or more grooves 120 in the superhard
bearing elements 108 before or after securing the superhard bearing
elements 108 to the support ring 102. For example, suitable
laser-cutting techniques are disclosed in U.S. application Ser. No.
13/166,007 filed on Jun. 22, 2011, the disclosure of which is
incorporated herein, in its entirety, by this reference.
[0050] As shown in FIG. 1E, some or all of the grooves 120 may
follow a generally straight path along the lateral surface 108B
with a length L that extends axially generally between the bearing
surface 114 and a bottom surface 108A of the superhard bearing
element 108. Such a configuration may develop eddies in the
lubricating fluid flowing generally traverse to the grooves 120 to
enhance the cooling of the lubricating fluid. In other embodiments,
the length L of some or all of the grooves 120 may extend along
only a portion of the lateral surface 108B. For example, as shown
in FIG. 1G, the grooves 120 may extend between the bearing surface
114 and a first location above the bottom surface 108A of the
superhard bearing element 108. In an embodiment, the first location
may generally correspond to an upper surface of the support ring
102 such that the grooves 120 extend between the bearing surface
114 and the upper surface of the support ring 102. Such a
configuration may help to secure the superhard bearing elements 108
within the recesses 106. For example, brazed-joint strength between
the superhard bearing element 108 the recess 106 may be improved by
providing a lateral surface on the portion of the superhard bearing
element 108 within the recess 106 that generally corresponds to the
lateral surface of the recess 106. Moreover, while the grooves 120
are illustrated following a generally straight path, some or all of
the grooves 120 may follow a generally arcuate path, a generally
semi-cylindrical path, a generally S-shaped path, a generally
U-shaped path, a generally V-shaped path, a generally linear path,
or any other suitable path.
[0051] In an embodiment, the length L of the grooves 120 may be
about 0.3 inches to about 1 inch, such as about 0.25 inches to
about 0.5 inch or about 0.10 inch to about 0.3 inch. However, in
other embodiments, the length L of the grooves 120 may be longer or
shorter than the foregoing ranges. As illustrated, each of the
grooves 120 may have at least substantially the same length L.
However, in other embodiments, some or all of the grooves 120 may
have substantially different lengths L, respectively. For example,
in an embodiment, the superhard bearing elements 108 may include a
first group of grooves 120 having lengths L of about 0.25 inch and
a second group of grooves 120 having lengths L of about 0.5
inches.
[0052] While all the superhard bearing elements 108 are shown
including substantially identical grooves 120, in other
embodiments, only a portion of the superhard bearing elements 108
may have substantially identical grooves 120, the superhard bearing
elements 108 may have grooves 120 of varying sizes and/or
configurations, or only some of the superhard bearing elements 108
may include grooves 120.
[0053] The superhard bearing element 108 may have a height
extending between the bearing surface 114 and the bottom surface
108A. In an embodiment, the relationship between the length L of
the grooves 120 and the height of the superhard bearing elements
108 may be configured to influence cooling, lubrication and/or
bearing capacity of the superhard bearing elements 108 and/or
support ring 102. The length L of at least one of the grooves 120
may be at least: about five (5) percent; about fifteen (15)
percent; about twenty five (25) percent; about fifty (50) percent;
about seventy (70) percent; about eighty (80) percent; or about one
hundred (100) percent of the height of the superhard bearing
elements 108. In other embodiments, the length L of one or more of
the grooves 120 may be about two (2) percent to about one hundred
(100) percent; about ten (10) percent to about ninety (90) percent;
or at least about twenty (20) percent of the height of at least one
of the superhard bearing elements 108. In other embodiments, the
length L of one or more of the grooves 120 and the height of one or
more of the superhard bearing elements 108 may be larger or smaller
relative to each other.
[0054] As illustrated in FIG. 1F, each of the grooves 120 may be
further defined by a bottom portion 120B and opposing sidewalls
120A. In an embodiment, the grooves 120 may include edge features
configured to influence flow conditions. For example, the grooves
120 may include beveled edges, rounded edges, chamfered edges, or
the like. One or more of the grooves 120 may include edges that are
sharpened, have notches, irregularly shaped, combinations thereof,
or the like. Such a configuration may allow the grooves 120 to
partially agitate, break-up or create desired flow characteristics
in the lubricating fluid.
[0055] The grooves 120 may be substantially equidistantly and
circumferentially distributed about a lateral periphery of the
superhard bearing element 108. In other embodiments, the grooves
120 may be unevenly distributed about the periphery of the
superhard bearing element 108. For example, the superhard bearing
element 108 may include two grooves 120 on a first side of the
lateral surface 108B and no grooves on a second side of the lateral
surface 108B generally opposite the first side. In an embodiment,
one or more of the grooves 120 may be formed generally parallel to
an axis 122 of the superhard bearing element 108. In other
embodiments, one or more of the grooves 120 may be generally
non-parallel to the axis 122 of the superhard bearing element
108.
[0056] In an embodiment, the grooves 120 may have a generally
V-shaped cross-section such that the bottom portion 120B is at
least partially defined by the intersection of the opposing
sidewalls 120A. In other embodiments, the grooves 120 may have a
generally rectangular cross-section, a generally U-shaped
cross-section, a generally semi-circular shaped cross-section, a
generally parabolic shaped cross-section, a generally trapezoidal
shaped cross-section, combinations thereof, or the like. The
cross-section of the grooves 120 may influence the flow conditions
of the lubricating fluid and/or the cooling of the superhard
bearing elements 108. For example, in an embodiment, at least one
of the grooves 120 may have a portion including a V-shaped
cross-section configured to improve cooling of the superhard
bearing element 108 and/or lubrication of the bearing surface 114
by increasing the fluid velocity of the lubricating fluid through
that portion of the groove 120 and/or increasing the surface area
in contact with the lubricating fluid. In other embodiments, the
grooves 120 may include a first deeper cross-sectional shape
followed by a second shallower cross-sectional shape to pump or
impel the lubricating fluid.
[0057] Referring still to FIG. 1F, at least one of the grooves 120
may have a width W and a depth D. Variations of the depth D and/or
the width W of the grooves 120 may help the grooves 120 lubricate
and/or cool the superhard bearing elements 108. As shown in FIG.
1F, the depth D of the grooves 120 extends between the bottom
portion of the grooves 120 and the lateral surface 108B. For
example, the depth D may be about 0.1 inches to about 0.4 inches,
such as about 0.15 inches to about 0.25 inches. As illustrated, the
grooves 120 may have at least substantially the same depth D.
However, in other embodiments, the grooves 120 may have at least
substantially different depths D. In addition, the depths D of a
groove 120 may vary along its path. For example, at least one of
the grooves 120 may have a depth D that includes a deeper portion
and a shallower portion.
[0058] As shown in FIG. 1F, the width W of the grooves 120 extends
between the grooves 120. In an embodiment, the widths W of the
grooves 120 may vary. For example, some or all of the grooves 120
may have a width W that tapers from the lateral surface 108B of the
superhard bearing element 108 toward the bottom portion of the
grooves 120. Such a configuration may provide the grooves 120 with
a wider inlet for the lubricating fluid. In an embodiment, the
width W of the grooves 120 may be about 0.1 inches to about 0.5
inches, such as about 0.2 inches to about 0.3 inches. In other
embodiments, the widths W of the grooves 120 may be wider or
narrower. As illustrated, the grooves 120 may have at least
substantially the same width W. However, in other embodiments, some
or all of the grooves 120 may have substantially different widths
W.
[0059] In an embodiment, the relationship between the length L of
one or more of the grooves 120 and the depth D of one or more of
the grooves 120 may be configured to improve cooling, lubrication,
and/or bearing capacity of the superhard bearing elements 108
and/or the support ring 102. For example, the length L of at least
one of the grooves 120 may be at least: about one hundred (100)
percent; about two hundred (200) percent; about three hundred (300)
percent; about four hundred (400) percent; about five hundred (500)
percent; about six hundred (600) percent; about seven hundred (700)
percent; or about eight hundred (800) percent of the depth D of at
least one of the grooves 120. In addition, the length L of at least
one of the grooves 120 may be: about four hundred (400) percent to
eight hundred (800) percent; or about five hundred (500) percent to
seven hundred (700) percent of the depth of the grooves 120; or
about six hundred (600) percent of the depth D of at least one of
the grooves 120. In other embodiments, the depth D of one or more
of the grooves 120 and the length L of one or more of the grooves
120 may be larger or smaller relative to each other.
[0060] In an embodiment, the relationship between the length L of
one or more of the grooves 120 and the width W of one or more of
the grooves 120 may be configured to improve cooling, lubrication,
and/or bearing capacity of the superhard bearing elements 108
and/or the support ring 102. For example, the length L of at least
one of the grooves 120 may be at least: about one hundred (100)
percent; about two hundred (200) percent; about three hundred (300)
percent; about four hundred (400) percent; about five hundred (500)
percent; about six hundred (600) percent; about seven hundred (700)
percent; or about eight hundred (800) percent of the width W of at
least one of the grooves 120. In addition, the length L of at least
one of the grooves 120 may be: about four hundred (400) percent to
about eight hundred (800) percent; or about five hundred (500)
percent to about seven hundred (700) percent; or at least about six
hundred (600) percent of the width W of at least one of the grooves
120. In other embodiments, the width W of one or more of the
grooves 120 and the length L of one or more of the grooves 120 may
be larger or smaller relative to each other.
[0061] In an embodiment, the relationship between the depth D of
one or more of the grooves 120 and the width W of the one or more
of the grooves 120 may be configured to improve cooling,
lubrication, and/or bearing capacity of the superhard bearing
elements 108 and/or the support ring 102. For example, the depth D
of at least one of the grooves 120 may be at least: about fifty
(50) percent; about one hundred (100) percent; about one hundred
and fifty (150) percent; about two hundred (200) percent; or about
three hundred (300) percent of the width W of at least one of the
grooves 120. In addition, the depth D of at least one of the
grooves 120 may be about fifty (50) percent to about one hundred
and fifty (150) percent; or about one hundred (100) percent of the
width W of at least one of the grooves 120. In other
configurations, the depth D of one or more of the grooves 120 and
the width W of one or more of the grooves 120 may be larger or
smaller relative to each other.
[0062] FIGS. 2A-2C are isometric, side elevation, and top plan
views of a superhard bearing element 208 according to an
embodiment. The superhard bearing element 208 may include a
superhard table 210 bonded to a substrate 212, and a bearing
surface 214 of the superhard table 210. The superhard bearing
element 208 may be made from any of the materials discussed above
for the superhard bearing elements 108. In the illustrated
embodiment, the superhard bearing element 208 may have a generally
cylindrical shape. In other embodiments, however, the superhard
bearing element 208 may have a generally rectangular shape, a
generally oval shape, a generally diamond shape, a generally
triangular shape, a generally non-cylindrical shape, or other
suitable shape.
[0063] The superhard bearing element 208 may include a plurality of
grooves 220 formed in a lateral surface 208B of the superhard
bearing element 208. The superhard bearing element 208 may include
two, four, seven, or any suitable number of grooves 220. Some or
all of the grooves 220 may follow a generally straight path along
the lateral surface 208B generally parallel to an axis 222 of the
superhard bearing elements 208. While the grooves 220 are
illustrated generally parallel to the axis 222 of the superhard
bearing elements 208, the one or more of the grooves 220 may be
formed generally nonparallel to the axis 222 of the superhard
bearing elements 208. For example, the grooves 220 may follow a
generally curved path, a generally S-shaped path, a generally
helical path, a generally V-shaped path, or the like. In an
embodiment, some or all of the grooves 220 may have a length L that
extends generally between the bearing surface 214 and a bottom
surface 208A. In another embodiment, the length L of some or all of
the grooves 220 may extend only through a first location between
the bearing surface 214 and the bottom surface 208A and a second
location. In other embodiments, some or all of the grooves 220 may
have a length L that extends through a portion of the bearing
surface 214, through a portion of the substrate 212, or a
combination thereof.
[0064] As illustrated in FIG. 2C, the groove 220 may include a
cross-sectional area at least partially defined between sidewalls
220A and a bottom portion 220B. In an embodiment, the
cross-sectional shape may be generally U-shaped. Such a
configuration may increase surface area and/or cause the
lubricating fluid flowing across the grooves 220 to abruptly slow
and change flow direction to enhance heat removal from the
superhard bearing elements 208 to thereby reducing the risk of the
superhard bearing elements 208 overheating. Moreover, flow of the
lubricating fluid generally traverse to the grooves 220 may create
eddies in the lubricating fluid to enhance the cooling effect of
the lubricating fluid. In other embodiments, the grooves 220 may
have a generally v-shaped cross-section, a generally circular
cross-section, a generally rectangular cross-section, a generally
rounded rectangular shape, a generally trapezoidal cross-section,
combinations thereof, or the like.
[0065] FIGS. 3A-3C are isometric, side elevation, and top plan
views of a superhard bearing element 308 according to an
embodiment. The superhard bearing element 308 may include a
superhard table 310 bonded to a substrate 312, and a bearing
surface 314 of the superhard table 310. The superhard bearing
element 308 may be made from any of the materials discussed in
relation to the superhard bearing elements 108. In the illustrated
embodiment, the superhard bearing element 308 may have a generally
cylindrical shaped body. In other embodiments, however, the
superhard bearing element 308 may have a generally rectangular
shape, a generally oval shape, a generally wedge shape, a generally
triangular shape, or other suitable shape.
[0066] The superhard bearing element 308 may include a groove 320
formed in a lateral surface 308B of the superhard bearing element
308. In other embodiments, the superhard bearing element 308 may
include two, three, or ten, or any suitable number of grooves
320.
[0067] The groove 320 may follow a path generally extending along a
right-handed or left-handed curve or helix. The one or more grooves
320 may follow a generally helical path, a generally double helical
path, a generally spiral path, or other suitable path. In an
embodiment, the path may correspond to a length of the one or more
grooves 320. The groove 320 may extend about the periphery of the
superhard bearing element 308 between about two (2) and ten (10)
times, or more. Such a configuration may allow the lubricating
fluid to flow about the superhard bearing element 308 in a
spiraling pattern to enhance heat removal from the superhard
bearing element 308. In other embodiments, the groove 320 may
extend about the periphery of the superhard bearing elements 308
less than one (1) time, five (5) times, seven (7) times, ten (10)
times, or any suitable number of times.
[0068] In an embodiment, the groove 320 may extend generally
between the bearing surface 314 and the bottom surface 308A of the
superhard bearing element 308. In other embodiments, the groove 320
may extend generally between the bearing surface 314 and a first
location between the bearing surface 314 and a bottom surface 308A.
In yet other embodiments, the groove 320 may extend generally
between the bottom surface 308A and a second location between the
bottom surface 308A and the bearing surface 314. In other
embodiments, the groove 320 may extend between a first location and
a second location.
[0069] FIGS. 4A and 4B are isometric and top plan views of a
thrust-bearing assembly 400 according to an embodiment. The
thrust-bearing assembly 400 may form a stator or a rotor of
thrust-bearing apparatus. As shown in FIGS. 4A and 4B, the
thrust-bearing assembly 400 may include a support ring 402 defining
an opening 404 through which a shaft (not shown) of, for example, a
downhole drilling motor may extend. Similar to the support ring
102, the support ring 402 may be made from a variety of different
materials. For example, the support ring 402 may comprise a metal,
alloy steel, a metal alloy, carbon steel, stainless steel, tungsten
carbide, or any other suitable conductive or non-conductive
material. The support ring 402 may also include a plurality of
recesses 406 (shown in FIG. 4C) formed therein.
[0070] The thrust-bearing assembly 400 further may include a
plurality of superhard bearing elements 408. In an embodiment, one
or more of the superhard bearing elements 408 may have a generally
wedge shaped body. In other embodiments, one or more of the
superhard bearing elements 408 may have a generally rectangular
body, a generally oval shaped body, or any other suitable shaped
body. The superhard bearing elements 408 may include a superhard
table 410 bonded to a substrate 412, and a bearing surface 414 of
the superhard table 410. The superhard bearing elements 408 are
illustrated in FIGS. 4A and 4B being distributed circumferentially
about a thrust axis 416 along which a thrust force may be generally
directed during use. The superhard bearing elements 408 may be
circumferentially distributed about the thrust axis 416 in one row,
two rows, three rows, or any number of suitable rows. As shown,
gaps 418 may be located between adjacent ones of the superhard
bearing elements 408 through which lubricating fluid may flow, as
illustrated by flow arrows 421. In an embodiment, at least one of,
some of, or all of the gaps 418 may exhibit a width of about
0.00020 inches to about 0.100 inches, such as about 0.00040 inches
to about 0.0010 inches, or about 0.00040 inches to about 0.080
inches. In other embodiments, the gaps 418 may have widths that are
relatively larger or smaller. In other embodiments, the gaps 418
may substantially be zero and the adjacent ones of the superhard
bearing elements 408 may abut each other. In other embodiments, one
or more of the gaps 418 may have different widths. For example, one
pair of adjacent ones of the superhard bearing elements 408 may be
closer together than another pair of adjacent ones of the superhard
bearing elements 408.
[0071] Each of the superhard bearing elements 408 may be partially
disposed in a corresponding one of the recesses 406 (shown in FIG.
4C) of the support ring 402. The superhard bearing elements 408 may
be partially positioned in and secured to the recesses 406 via
brazing, welding, soldering, press-fitting, threadly attaching,
fastening with a fastener, combinations of the foregoing, or
another suitable technique. Similar to the superhard bearing
elements 108, the superhard bearing elements 408 may be machined to
tolerances and mounted in the support ring 402 and/or attached to
the support ring 402. Bearing surfaces 414 may be planarized (e.g.,
by lapping and/or grinding) and/or positioned so that the bearing
surfaces 414 are substantially coplanar. Optionally, one or more of
the superhard bearing elements 408 may exhibit a peripherally
extending edge chamfer. However, in other embodiments, the edge
chamfer may be omitted.
[0072] FIGS. 4D-4F are isometric, side elevation, and top plan
views of a superhard bearing element 408 removed from the
thrust-bearing assembly 400. The superhard bearing element 408 may
be made from any of the materials discussed above for the superhard
bearing elements 108. The superhard bearing elements 408 may
include a first lateral surface 408A, a second lateral surface
408B, a first end surface 408C, and a second end surface 408D. The
first lateral surface 408A and the second lateral surface 408B of
each of the superhard bearing elements 408 may extend between the
first end surface 408C and the second end surface 408D and vice
versa. In an embodiment, the first lateral surface 408A and the
second lateral surface 408B may be non-parallel to each other such
that the superhard bearing elements 408 have a wedge-like shape. In
the illustrated embodiment, both the first end surface 408C and the
second end surface 408D may have a convex curvature. In other
embodiments, the first end surface 408C and the second end surface
408D may have symmetrical edge configurations, asymmetrical edge
configurations, curved edge configurations, irregular edge
configurations, or other suitable edge configurations. For example,
the first end surface 408C and the second end surface 408D may take
the form of any portion of a circle, oval, square, rectangle,
rhombus, triangle, or virtually any other simple, complex, regular,
irregular, or non-symmetrical geometric shape. Optionally, the
first end surface 408C may have an area greater than an area of the
second end surface 408D. In other embodiments, the first end
surface 408C and the second end surface 408D may be substantially
the same size.
[0073] Like the superhard bearing elements 108, 208, and 308, one
or more of the superhard bearing elements 408 may include one or
more features (e.g., at least one groove) configured to influence
bearing capacity and/or influence cooling of the superhard bearing
elements 408. For example, one or more grooves 420 may be formed in
the first lateral surface 408A and/or the second lateral surface
408B of the superhard bearing elements 408. One or more of the
grooves 420 may be formed by CNC milling, EDM, laser-cutting,
grinding, combinations thereof, or otherwise machining the one or
more grooves 420 in the superhard bearing elements 408 before or
after securing the superhard bearing elements 408 to the support
ring 402.
[0074] In an embodiment, the grooves 420 may be formed
substantially parallel to the bearing surface 414 of the superhard
bearing element 408. Some or all of the grooves 420 may have a
length that extends along a path between the first end surface 408C
and the second end surface 408D, or vice versa. In other
embodiments, the length L of some or all of the grooves 420 may
extend along only a portion of the first lateral surface 408A
and/or the second lateral surface 408B. For example, the length L
of a groove 420 may extend between the first end surface 408C and
an intermediate location between the first end surface 408C and the
second end surface 408D. Moreover, while the grooves 420 are
illustrated following a generally straight path, some or all of the
grooves 420 may follow a generally curved path, a generally
s-shaped path, a generally sinusoidal path, or any other suitable
path. As illustrated, each of the grooves 420 may have at least
substantially the same length L. However, in other embodiments,
some or all of the grooves 420 may have substantially different
lengths L, respectively. Some or all of the grooves 420 may be
further defined by a bottom portion and opposing sidewalls. Similar
to the grooves 120, at least one of the grooves 420 may have a
width W (not shown) and a depth D (not shown). Variations in the D
and/or the width W of the grooves 420 may help the grooves 420
lubricate and/or cool the superhard bearing elements 408. While all
the superhard bearing elements 408 are shown including
substantially identical grooves 420, in other embodiments, only a
portion of the superhard bearing elements 408 may have
substantially identical grooves 420 and/or the superhard bearing
elements 408 may have grooves 420 of varying sizes and/or
configurations. The grooves 420 may include edge features
configured to influence flow conditions of the lubricating fluid.
For example, the grooves 420 may include beveled edges, rounded
edges, chamfered edges, or the like. One or more of the grooves may
include edges that are sharpened, notched, irregularly shaped,
combinations thereof, or the like. Such a configuration may allow
the grooves 420 to partially agitate, break-up or create desired
flow characteristics in the lubricating fluid.
[0075] The grooves 420 may be formed in rows positioned between the
bearing surface 414 and a first location above a bottom surface of
the superhard bearing element 408. In an embodiment, the first
location may generally correspond to an upper surface 402A of the
support ring 402 such that the grooves 420 are positioned between
the bearing surface 414 and the upper surface 402A of the support
ring 402 during operation of the thrust-bearing assembly 400. In
other embodiments, the first location may be below the upper
surface 402A of the support ring 402. In yet other embodiments, the
grooves 420 may be formed in rows positioned substantially between
the bearing surface 414 and the bottom surface of the superhard
bearing element 408 as shown in FIG. 4G. Such a configuration may
allow the grooves 420 to be located within the recesses 406 during
operation of the thrust-bearing assembly 400. In other embodiments,
the position of the rows of grooves 420 may vary from one superhard
bearing element 408 to another.
[0076] Referring again to FIG. 4C, the grooves 420 may influence
flow conditions between adjacent ones of the superhard bearing
elements 408 during operation of the thrust-bearing assembly 400.
For example, as shown by the flow arrow 421, the grooves 420 may
increase the surface area of the superhard bearing elements 408 in
contact with lubricating fluid flowing between adjacent ones of the
superhard bearing elements 408. In an embodiment, the grooves 420
may direct lubricating fluid flowing between adjacent ones of the
superhard bearing elements 408 about and/or over the superhard
bearing elements 408 and/or the support ring 402. For example, at
least some of the grooves 420 may extend along a curved path toward
the bearing surface 414. In another embodiment, the grooves 420 may
increase the surface area of the superhard bearing elements 408 to
enhance the heat transfer rate of the superhard bearing element
408.
[0077] Embodiments of the invention further include other surface
topographies that may be formed into a lateral surface of a
superhard bearing element. For example, dimpled, textured,
recessed, cross-hatched, or other surface features or topography
may be employed for increasing heat transfer from a superhard
bearing element. In an embodiment, as shown in FIG. 4H, the lateral
surface of the superhard bearing element 408 may include a
plurality of dimples 431 formed therein to help enhance heat
removal from the superhard bearing element 408. The dimples 431 may
cover substantially the entire lateral surface, extending between
the bearing surface 414 and a bottom surface of the superhard
bearing element 408 and the second end surface 408D and the first
end surface (not shown). The dimples 431 may be generally concavely
shaped, variably sized, or uniformly distributed. Flow of the
lubricating fluid over the dimples 431 may create small vortices
and/or increase the surface area of the lateral surface in contact
with the lubricating fluid to help enhance heat removal from the
superhard bearing element 408. While the dimples 431 are
illustrated being generally concave, variably sized, and evenly
distributed, in other embodiments, the dimples 431 may have other
suitable shapes, sizes, and/or distributions. For example, the
dimples 431 may be generally triangular shaped or cubic shaped and
may be staggered, similarly sized, and only on a portion of the
lateral surface.
[0078] In another embodiment, the lateral surface of the superhard
bearing element 408 may be cross-hatched to help enhance heat
removal from the superhard bearing element 408. As shown in FIG.
4I, the cross-hatch 433 may include a plurality of intersecting
grooves extending between the bearing surface 414, the bottom
surface, the second end surface 408D, and the first end surface
(not shown) of the superhard bearing element 408. The cross-hatch
433 may increase the surface area of the superhard bearing element
408 in contact with the lubricating fluid to help remove heat from
the superhard bearing element 408. Moreover, the cross-hatch 433
may direct lubricating fluid about and/or over the superhard
bearing element 408 to enhance heat removal.
[0079] Any of the above-described thrust-bearing assembly
embodiments may be employed in a thrust-bearing apparatus. FIG. 5A
is an isometric view of a thrust-bearing apparatus 500. The
thrust-bearing apparatus 500 may include a stator 540 configured as
any of the previously described embodiments of thrust-bearing
assemblies. The stator 540 may include a plurality of
circumferentially-adjacent superhard bearing elements 508. The
superhard bearing elements 508 may include a bearing surface 514
and at least some of the superhard bearing elements 508 may
exhibit, for example, the configuration of the superhard bearing
elements 108. The superhard bearing elements 508 may be mounted or
otherwise attached to a support ring 502. The thrust-bearing
apparatus 500 further may include a rotor 550. The rotor 550 may
include a support ring 552 and a plurality of superhard bearing
elements 558 mounted or otherwise attached to the support ring 552,
with each of the superhard bearing elements 558 having a bearing
surface 554. As shown, a shaft 556 may be coupled to the support
ring 552 and operably coupled to an apparatus capable of rotating
the shaft 556 in a direction R (or in a generally opposite
direction), such as a downhole motor. For example, the shaft 556
may extend through and may be secured to the support ring 552 of
the rotor 550 by press-fitting or threadly coupling the shaft 556
to the support ring 552 or another suitable technique. A housing
560 may be secured to the support ring 502 of the stator 540 and
may extend circumferentially about the shaft 556 and the rotor
550.
[0080] FIG. 5B is a cross-sectional view in which the shaft 556 and
housing 560 are not shown for clarity. In operation, lubricating
filling fluid, or mud may be pumped between the shaft 556 and the
housing 560, and between the superhard bearing elements 558 of the
rotor 550. Grooves 520 of the superhard bearing elements 558 of the
rotor 550 may help direct lubricating fluid over and/or around the
superhard bearing elements 508 and 558 which in turn can greatly
reduce friction between the bearing surfaces 514 of the stator 540
and the bearing surfaces 554 of the rotor 550. The grooves 520 may
also help cool the superhard bearing elements 558 of the rotor 550
by increasing the surface area of the superhard bearing elements
558 in contact with the lubricating fluid thus improving bearing
capacity. In other embodiments, the grooves 520 help cool the
support ring 552 of the rotor 550 by increasing the surface area of
the support ring 552 in contact with the lubricating fluid. In
addition, the grooves 520 may help improve bearing capacity by
increasing heat removal from the thrust-bearing apparatus 500 to
influence potential annealing. Moreover, under certain operational
conditions the thrust-bearing apparatus 500 may be operated as a
hydrodynamic bearing. For example, where the rotational speed of
the rotor 550 is sufficiently great and the thrust load is
sufficiently low, a fluid film may develop between the bearing
surfaces 514 of the stator 540 and the bearing surfaces 554 of the
rotor 550. The fluid film may have sufficient pressure to reduce or
prevent contact between the respective bearing surfaces 514, 554
and thus, substantially reduce wear of the superhard bearing
elements 558 and/or the superhard bearing elements 508. In such a
situation, the thrust-bearing apparatus 500 may be described as
operating hydrodynamically. Thus, the thrust-bearing apparatus 500
may be operated to improve lubrication, cooling, bearing capacity,
and/or as a hydrodynamic bearing.
[0081] The concepts used in the thrust-bearing assemblies and
apparatuses described above may also be employed in the radial
bearing assemblies and apparatuses. FIGS. 6A and 6B are isometric
and isometric cutaway views, respectively, illustrating a radial
bearing assembly 600 according to an embodiment. The radial bearing
assembly 600 may include a support ring 602 extending about a
rotation axis 616. The support ring 602 may include an inner
peripheral surface 602C defining a central opening 604 that is
capable of receiving, for example, an inner support ring or inner
race. The support ring 602 may also include an outer peripheral
surface 602D. A plurality of superhard bearing elements 608 may be
distributed circumferentially about the rotation axis 616. Each
superhard bearing element 608 may include a superhard table 610
including a concavely-curved bearing surface 614 (e.g., curved to
lie on an imaginary cylindrical surface). Each superhard table 610
may be bonded or attached to a corresponding substrate 612 (shown
in FIG. 6B). The superhard bearing elements 608 may have a
generally cylindrical shape and each made from any of the materials
discussed above for the superhard bearing elements 108. In other
embodiments, the superhard bearing elements 608 may have a
non-cylindrical shape, a generally wedge-like shape, a generally
rectangular shape, a circular shape, or any other suitable shape.
In an embodiment, at least some of the superhard bearing elements
608 may include a plurality of grooves 620 formed in a lateral
surface 608C of the superhard bearing element 608. The grooves 620
may be configured similar to the grooves 120, 220, 320, 420, or any
other groove disclosed herein. As illustrated in FIGS. 6A and 6B,
the superhard bearing elements 608 may be distributed
circumferentially about the rotation axis 616 in corresponding
recesses 606 formed in the support ring 602 and arranged in a
single row. In other embodiments, the superhard bearing elements
608 may be circumferentially distributed in two rows, three rows,
four rows, or any number of rows.
[0082] FIG. 7 is an isometric cutaway view of a radial bearing
apparatus 700 according to an embodiment. The radial bearing
apparatus 700 may include an inner race 782 (i.e., a rotor). The
inner race 782 may define an opening 704 and may include a
plurality of circumferentially-adjacent superhard bearing elements
786 distributed about a rotation axis 716, each of which includes a
convexly-curved bearing surface 788. The radial bearing apparatus
700 may further include an outer race 790 (i.e., a stator) that
extends about and receives the inner race 782. The outer race 790
may include a plurality of circumferentially-adjacent superhard
bearing elements 708 distributed about the rotation axis 716, each
of which includes a concavely-curved bearing surface 714 curved to
correspond to the convexly-curved bearing surfaces 788. The
superhard bearing elements 708 and 786 may have a generally
cylindrical shape and each may be made from any of the materials
discussed above for the superhard bearing elements 108. In other
embodiments, the superhard bearing elements 708 and 786 may have a
generally wedge-like shape, a generally rectangular shape, a
non-cylindrical shape, or any other suitable shape. The terms
"rotor" and "stator" refer to rotating and stationary components of
the radial bearing apparatus 700, respectively. Thus, if the outer
race 790 is configured to remain stationary, the outer race 790 may
be referred to as the stator and the inner race 782 may be referred
to as the rotor.
[0083] At least some of the superhard bearing elements 786 and/or
the superhard bearing elements 708 may include a plurality of
grooves 720 formed in a lateral surface thereof. One or more of the
grooves 720 may be configured to influence lubrication, cooling,
and/or bearing capacity of the superhard bearing elements 786, 708
and/or the inner race 782 and/or the outer race 790. Moreover,
under certain operating conditions the grooves 720 may help form a
fluid film similar to the description in relation to FIGS. 5A and
5B. A shaft or spindle (not shown) may extend through the opening
704 and may be secured to the rotor 782 by press-fitting the shaft
or spindle to the rotor 782, threadly coupling the shaft or spindle
to the rotor 782, or another suitable technique. A housing (not
shown) may also be secured to the stator 790 using similar
techniques.
[0084] The radial bearing apparatus 700 may be employed in a
variety of mechanical applications. For example, so-called "rotary
cone" rotary drill bits, pumps, transmissions or turbines may
benefit from a radial bearing apparatus discussed herein.
[0085] It is noted that the outer race 790 of the radial bearing
apparatus 700 is shown also including a plurality of
circumferentially-distributed superhard bearing elements 708 with a
plurality of grooves configured to influence lubrication, cooling,
and/or bearing capacity of the radial bearing apparatus 700.
However, in other embodiments, an outer race or the inner race of a
radial bearing apparatus may include a plurality of
circumferentially distributed superhard bearing elements without
grooves.
[0086] Any of the embodiments for bearing apparatuses discussed
above may be used in a subterranean drilling system. FIG. 8 is a
schematic isometric cutaway view of a subterranean drilling system
800 according to an embodiment. The subterranean drilling system
800 may include a housing 860 enclosing a downhole drilling motor
862 (i.e., a motor, turbine, or any other device capable of
rotating an output shaft) that may be operably connected to an
output shaft 856. A thrust-bearing apparatus 864 may be operably
coupled to the downhole drilling motor 862. The thrust-bearing
apparatus 864 may be configured as any of the previously described
thrust-bearing apparatus embodiments. A rotary drill bit 868 may be
configured to engage a subterranean formation and drill a borehole
and may be connected to the output shaft 856. The rotary drill bit
868 is a fixed-cutter drill bit and is shown comprising a bit body
890 having radially-extending and longitudinally-extending blades
892 with a plurality of PDCs secured to the blades 892. However,
other embodiments may utilize different types of rotary drill bits,
such as core bits and/or roller-cone bits. As the borehole is
drilled, pipe sections may be connected to the subterranean
drilling system 800 to form a drill string capable of progressively
drilling the borehole to a greater size or depth within the
earth.
[0087] The thrust-bearing apparatus 864 may include a stator 872
that does not rotate and a rotor 874 that may be attached to the
output shaft 856 and rotates with the output shaft 856. As
discussed above, the thrust-bearing apparatus 864 may be configured
as any of the embodiments disclosed herein. For example, the stator
872 may include a plurality of circumferentially-distributed
superhard bearing elements 876 similar to the superhard bearing
elements 508 shown and described in the thrust-bearing apparatus
500 of FIG. 5A. The rotor 874 may include a plurality of
circumferentially-distributed superhard bearing elements (not
shown) such as shown and described in relation to FIGS. 1A-4G.
[0088] In operation, drilling fluid may be circulated through the
downhole drilling motor 862 to generate torque and rotate the
output shaft 856 and the rotary drill bit 868 attached thereto so
that a borehole may be drilled. A portion of the drilling fluid may
also be used to lubricate opposing bearing surfaces of the stator
872 and the rotor 874. When the rotor 874 is rotated, grooves of
the superhard bearing elements of the rotor 874 may pump the
drilling fluid onto the bearing surfaces of the stator 872 and/or
the rotor 874, as previously discussed.
[0089] Although the bearing assemblies and apparatuses described
above have been discussed in the context of subterranean drilling
systems and applications, in other embodiments, the bearing
assemblies and apparatuses disclosed herein are not limited to such
use and may be used for many different applications, if desired,
without limitation. Thus, such bearing assemblies and apparatuses
are not limited for use with subterranean drilling systems and may
be used with various mechanical systems, without limitation.
[0090] While various aspects and embodiments have been disclosed
herein, other aspects and embodiments are contemplated. The various
aspects and embodiments disclosed herein are for purposes of
illustration and are not intended to be limiting. Additionally, the
words "including," "having," and variants thereof (e.g., "includes"
and "has") as used herein, including the claims, shall be open
ended and have the same meaning as the word "comprising" and
variants thereof (e.g., "comprise" and "comprises").
* * * * *